Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 242158
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
158 PM PST Wed Dec 24 2014

.Synopsis...
Rain and snow will end this evening as a cold front moves out of
the area. Dry weather and breezy winds are expected for Christmas Day.
There is a slight chance of light showers across the northern
mountains Sunday...otherwise dry Friday through the middle of next
week. Morning valley fog is possible Saturday and Sunday.

&&

.Discussion...
System making its way across the area this afternoon. Current
forecast still holding up well with little to no precipitation
falling in portions of the valley. The heaviest snow is still
expected in the 2 to 5 pm timeframe. This will cause travel
headaches across the Sierra as snow levels drop rapidly and
southwest winds pick up. Going winter wx advisory will continue as
is altho snow may be done before the 8pm expiration time
especially across northern most portions of the mountains. Precip
should shift south of the area by 7-8 pm timeframe leaving dry
conditions. Skies should clear out rapidly as the cold front exits
and results in cooler temperatures especially across higher
elevations. Weather for Christmas Day should be uneventful
although breezy winds will continue as northerly flow moves in.
High pressure settles in through at least the weekend with
decreasing winds and dry weather. This will allow for daytime temperatures
a few degrees warmer Friday into the weekend. Valley fog will
again become a concern Friday night into Saturday morning and
again Saturday night into Sunday morning with light flow, mostly
clear skies, and lingering surface moisture.

CEO

&&

.Extended Discussion (Sunday through Wednesday)

Extended models continue to show a very high amplitude ridge just
offshore the west coast on Sunday. A shortwave will slide down the
eastern side of the ridge which may brush the mountains in far
NorCal, but very little moisture is associated with that system so
little impact to our region. This ridge will continue to hug the
west coast into next week maintaining a dry weather pattern for
NorCal. The main impact this ridge will bring to our region are
breezy to strong northerly winds. Several pulses move through
NorCal which will periodically enhance these winds. By Wednesday,
the ridge axis moves closer to the coast which will begin to weaken
winds. JBB/JClapp

&&

.Aviation...

Most valley TAF sites are clearing to VFR this afternoon with
local spots still in MVFR conditions. Breezy southerly winds
during the current frontal passage. TAF sites have been
experiencing sustained winds 8 to 18 kts with gusts 20 to 30 kts.
This is a fairly quick moving system and winds will switch behind
the cold front. Expect winds to become northerly for KRDD & KRBL
around 00z and then for KSAC, KSMF, KMHR, and KSCK sites closer to
02z. The strong pressure gradient behind this front will cause
these Northerly winds to be breezy this evening. TAF site winds
will strengthen tomorrow after 16z peaking between 15 to 25 kts in
the valley during late morning and afternoon hours. The increased
winds should prevent fog development tomorrow morning. JBB


&&

.STO Watches/Warnings/Advisories...
winter weather advisory until 8 pm pst this evening above 4000
feet in the west slope northern sierra nevada...western plumas
county/lassen park.

&&

$$







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